diff --git a/test/plugins/base.plugin.bats b/test/plugins/base.plugin.bats
index 6022451a..11b8ee0c 100644
--- a/test/plugins/base.plugin.bats
+++ b/test/plugins/base.plugin.bats
@@ -8,37 +8,39 @@ function local_setup_file() {
 }
 
 @test 'plugins base: ips()' {
-  declare -r localhost='127.0.0.1'
+  readonly localhost='127.0.0.1'
   run ips
   assert_success
-  assert_line $localhost
+  assert_line "$localhost"
 }
 
 @test 'plugins base: myip()' {
+  local mask_ip
   run myip
   assert_success
-  declare -r mask_ip=$(echo $output | tr -s '[0-9]' '?')
-  [[ $mask_ip == 'Your public IP is:'*'?.?.?.?'* ]]
+  shopt -s extglob
+  mask_ip="${output//+([[:digit:]]|[[:digit:]][[:digit:]]|[[:digit:]][[:digit:]][[:digit:]])/?}" #$(echo "$output" | tr -s '0-9' '?')
+  [[ $mask_ip == 'Your public IP is:  ?.?.?.? ' ]]
 }
 
 @test 'plugins base: pickfrom()' {
-  stub_file="${BATS_TEST_TMPDIR}/stub_file"
-  printf "l1\nl2\nl3" > $stub_file
-  run pickfrom $stub_file
+  stub_file="${BATS_TEST_TMPDIR?}/stub_file"
+  printf "l1\nl2\nl3" > "$stub_file"
+  run pickfrom "$stub_file"
   assert_success
   [[ $output == l? ]]
 }
 
 @test 'plugins base: mkcd()' {
-  cd "${BATS_TEST_TMPDIR}"
+  cd "${BATS_TEST_TMPDIR?}"
   declare -r dir_name="-dir_with_dash"
 
   # Make sure that the directory does not exist prior to the test
-  rm -rf "${BATS_TEST_TMPDIR}/${dir_name}"
+  rm -rf "${BATS_TEST_TMPDIR:?}/${dir_name}"
 
   run mkcd "${dir_name}"
   assert_success
-  assert_dir_exist "${BATS_TEST_TMPDIR}/${dir_name}"
+  assert_dir_exist "${BATS_TEST_TMPDIR?}/${dir_name}"
 
   mkcd "${dir_name}"
   assert_equal "${PWD}" "${BATS_TEST_TMPDIR//\/\///}/${dir_name}"
@@ -46,20 +48,20 @@ function local_setup_file() {
 
 @test 'plugins base: lsgrep()' {
   for i in 1 2 3; do mkdir -p "${BASH_IT}/${i}"; done
-  cd $BASH_IT
+  cd "${BASH_IT?}"
   run lsgrep 2
   assert_success
-  assert_equal $output 2
+  assert_equal "$output" 2
 }
 
 @test 'plugins base: buf()' {
-  declare -r file="${BATS_TEST_TMPDIR}/file"
-  touch $file
+  declare -r file="${BATS_TEST_TMPDIR?}/file"
+  touch "$file"
 
   # Take one timestamp before running the `buf` function
   declare -r stamp1=$(date +%Y%m%d_%H%M%S)
 
-  run buf $file
+  run buf "$file"
 
   # Take another timestamp after running `buf`.
   declare -r stamp2=$(date +%Y%m%d_%H%M%S)
diff --git a/test/plugins/cmd-returned-notify.plugin.bats b/test/plugins/cmd-returned-notify.plugin.bats
index 04edad95..e120e9ef 100644
--- a/test/plugins/cmd-returned-notify.plugin.bats
+++ b/test/plugins/cmd-returned-notify.plugin.bats
@@ -1,4 +1,5 @@
 # shellcheck shell=bats
+# shellcheck disable=SC2034
 
 load "${MAIN_BASH_IT_DIR?}/test/test_helper.bash"
 
@@ -8,8 +9,8 @@ function local_setup_file() {
 }
 
 @test "plugins cmd-returned-notify: notify after elapsed time" {
-	export NOTIFY_IF_COMMAND_RETURNS_AFTER=0
-	export COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
+	NOTIFY_IF_COMMAND_RETURNS_AFTER=0
+	COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
 	sleep 1
 	run precmd_return_notification
 	assert_success
@@ -17,8 +18,8 @@ function local_setup_file() {
 }
 
 @test "plugins cmd-returned-notify: do not notify before elapsed time" {
-	export NOTIFY_IF_COMMAND_RETURNS_AFTER=10
-	export COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
+	NOTIFY_IF_COMMAND_RETURNS_AFTER=10
+	COMMAND_DURATION_START_SECONDS="${EPOCHREALTIME:-$SECONDS}"
 	sleep 1
 	run precmd_return_notification
 	assert_success
@@ -26,13 +27,13 @@ function local_setup_file() {
 }
 
 @test "lib command_duration: preexec no output" {
-	export COMMAND_DURATION_START_SECONDS=
+	COMMAND_DURATION_START_SECONDS=
 	run _command_duration_pre_exec
 	assert_success
 	assert_output ""
 }
 @test "lib command_duration: preexec set COMMAND_DURATION_START_SECONDS" {
-	export COMMAND_DURATION_START_SECONDS=
+	COMMAND_DURATION_START_SECONDS=
 	assert_equal "${COMMAND_DURATION_START_SECONDS}" ""
 	NOW="${EPOCHREALTIME:-$SECONDS}"
 	_command_duration_pre_exec
diff --git a/test/plugins/go.plugin.bats b/test/plugins/go.plugin.bats
index ebb9cd88..b8fb779a 100644
--- a/test/plugins/go.plugin.bats
+++ b/test/plugins/go.plugin.bats
@@ -1,4 +1,5 @@
 # shellcheck shell=bats
+# shellcheck disable=SC2034
 
 load "${MAIN_BASH_IT_DIR?}/test/test_helper.bash"
 
@@ -21,7 +22,7 @@ function setup_go_path()
 
 @test 'ensure _bash-it-gopath-pathmunge is defined' {
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
-  load ../../plugins/available/go.plugin
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
   run type -t _bash-it-gopath-pathmunge
   assert_line 'function'
 }
@@ -29,39 +30,39 @@ function setup_go_path()
 @test 'plugins go: single entry in GOPATH' {
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
   setup_go_path "$BASH_IT/test/fixtures/go/gopath"
-  load ../../plugins/available/go.plugin
-  assert_equal "$(cut -d':' -f1 <<<$PATH)" "$BASH_IT/test/fixtures/go/gopath/bin"
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
+  assert_equal "$(cut -d':' -f1 <<<"$PATH")" "$BASH_IT/test/fixtures/go/gopath/bin"
 }
 
 @test 'plugins go: single entry in GOPATH, with space' {
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
   setup_go_path "$BASH_IT/test/fixtures/go/go path"
-  load ../../plugins/available/go.plugin
-  assert_equal "$(cut -d':' -f1 <<<$PATH)" "$BASH_IT/test/fixtures/go/go path/bin"
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
+  assert_equal "$(cut -d':' -f1 <<<"$PATH")" "$BASH_IT/test/fixtures/go/go path/bin"
 }
 
 @test 'plugins go: single entry in GOPATH, with escaped space' {
   skip 'huh?'
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
   setup_go_path "$BASH_IT/test/fixtures/go/go\ path"
-  load ../../plugins/available/go.plugin
-  assert_equal "$(cut -d':' -f1 <<<$PATH)" "$BASH_IT/test/fixtures/go/go\ path/bin"
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
+  assert_equal "$(cut -d':' -f1 <<<"$PATH")" "$BASH_IT/test/fixtures/go/go\ path/bin"
 }
 
 @test 'plugins go: multiple entries in GOPATH' {
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
   setup_go_path "$BASH_IT/test/fixtures/go/gopath"
   setup_go_path "$BASH_IT/test/fixtures/go/gopath2"
-  load ../../plugins/available/go.plugin
-  assert_equal "$(cut -d':' -f1,2 <<<$PATH)" "$BASH_IT/test/fixtures/go/gopath2/bin:$BASH_IT/test/fixtures/go/gopath/bin"
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
+  assert_equal "$(cut -d':' -f1,2 <<<"$PATH")" "$BASH_IT/test/fixtures/go/gopath2/bin:$BASH_IT/test/fixtures/go/gopath/bin"
 }
 
 @test 'plugins go: multiple entries in GOPATH, with space' {
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
   setup_go_path "$BASH_IT/test/fixtures/go/gopath"
   setup_go_path "$BASH_IT/test/fixtures/go/go path"
-  load ../../plugins/available/go.plugin
-  assert_equal "$(cut -d':' -f1,2 <<<$PATH)" "$BASH_IT/test/fixtures/go/go path/bin:$BASH_IT/test/fixtures/go/gopath/bin"
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
+  assert_equal "$(cut -d':' -f1,2 <<<"$PATH")" "$BASH_IT/test/fixtures/go/go path/bin:$BASH_IT/test/fixtures/go/gopath/bin"
 }
 
 @test 'plugins go: multiple entries in GOPATH, with escaped space' {
@@ -69,6 +70,6 @@ function setup_go_path()
   { _command_exists go && go version &>/dev/null; } || skip 'golang not found'
   setup_go_path "$BASH_IT/test/fixtures/go/gopath"
   setup_go_path "$BASH_IT/test/fixtures/go/go path"
-  load ../../plugins/available/go.plugin
-  assert_equal "$(cut -d':' -f1,2 <<<$PATH)" "$BASH_IT/test/fixtures/go/go\ path/bin:$BASH_IT/test/fixtures/go/gopath/bin"
+  load "${BASH_IT?}/plugins/available/go.plugin.bash"
+  assert_equal "$(cut -d':' -f1,2 <<<"$PATH")" "$BASH_IT/test/fixtures/go/go\ path/bin:$BASH_IT/test/fixtures/go/gopath/bin"
 }
diff --git a/test/plugins/ruby.plugin.bats b/test/plugins/ruby.plugin.bats
index 7bfc6455..a6ff87c4 100644
--- a/test/plugins/ruby.plugin.bats
+++ b/test/plugins/ruby.plugin.bats
@@ -16,6 +16,7 @@ function local_setup_file() {
 }
 
 @test "plugins ruby: PATH includes ~/.gem/ruby/bin" {
+  local last_path_entry
   if ! type ruby >/dev/null; then
     skip 'ruby not installed'
   fi
@@ -26,6 +27,6 @@ function local_setup_file() {
   assert_success
   load "${BASH_IT?}/plugins/available/ruby.plugin.bash"
 
-  local last_path_entry="$(tail -1 <<<"${PATH//:/$'\n'}")"
+  last_path_entry="$(tail -1 <<<"${PATH//:/$'\n'}")"
   [[ "${last_path_entry}" == "$(ruby -e 'print Gem.user_dir')/bin" ]]
 }
diff --git a/test/plugins/xterm.plugin.bats b/test/plugins/xterm.plugin.bats
index 4cb1ffda..0d2c6298 100644
--- a/test/plugins/xterm.plugin.bats
+++ b/test/plugins/xterm.plugin.bats
@@ -1,4 +1,5 @@
 # shellcheck shell=bats
+# shellcheck disable=SC2034
 
 load "${MAIN_BASH_IT_DIR?}/test/test_helper.bash"
 
@@ -8,28 +9,28 @@ function local_setup_file() {
 }
 
 @test "plugins xterm: shorten command output" {
-    export SHORT_TERM_LINE=true
+    SHORT_TERM_LINE=true
     run _short-command "${BASH_IT}/test/fixtures/plugin/xterm/files"/*
     assert_success
     assert_output "${BASH_IT}/test/fixtures/plugin/xterm/files/arg0"
 }
 
 @test "plugins xterm: full command output" {
-    export SHORT_TERM_LINE=false
+    SHORT_TERM_LINE=false
     run _short-command "${BASH_IT}/test/fixtures/plugin/xterm/files"/*
     assert_success
     assert_output "$(echo "${BASH_IT}/test/fixtures/plugin/xterm/files"/*)"
 }
 
 @test "plugins xterm: shorten dirname output" {
-    export SHORT_TERM_LINE=true
+    SHORT_TERM_LINE=true
     run _short-dirname
     assert_success
     assert_output "$(basename "${PWD}")"
 }
 
 @test "plugins xterm: full dirname output" {
-    export SHORT_TERM_LINE=false
+    SHORT_TERM_LINE=false
     run _short-dirname
     assert_success
     assert_output "${PWD}"